This worked but it turns out it does a 302 redirect (a temporary redirect) as opposed to a permanent redirect, which is a 301. I could not find a way to make this work. What I ended up doing was the following:

[struts-config.xml]
Modified the old action element to use a new MyRedirAction class.

One gotcha that got me was that I assumed incorrectly that the query string (url parameters) would get passed along automatically in the redirect, but that was not the case. I had to add in the additional code to append the query string to the Location header variable.